Investment mixer



3,131,912 Patented May 5, 1964 3,131,912 INVESTMENT MIXER Edmund A.Steinbeck, Jr., Louisville, Ky., assignor to Edmund A. Steinbeck,Louisvilie, Ky. Filed Feb. 1, 1954, Ser. No. 407,337 6 Claims. (Cl.259-108) This invention relates to improvements in an investment mixer,particularly such a mixer when operated under vacuum or when operatedwith a vacuum on the materials being mixed.

This invention relates to improvements disclosed and claimed in pendingapplication of Edmund A. Steinbeck, Jr. and Robert Nieman for InvestmentMixer, Serial No. 255,704 filed November 9, 1951, now Patent Number2,777,177.

As stated in said pending application, it has been found that certainadvantages, particularly when using certain investment compositions, areobtained when the mixing or spatulation of the ingredients is eifectedat a relatively high rate of speed and these advantages consisting in asmoother extremely creamy mix from which the air can be more readilyextracted, and in which the time of mixing is materially reduced. Thesmoother, creamier mix further results in a smoother surface for themold cavity and a smoother surface on and a' more accurately fitting ofthe resulting casting from said mold cavity.

Investment mixers of the class of the present invention are generally.motor driven to obtain said higher speed of mixing or spatulation and inthe past it has been difficult to effect the proper drive connectionbetween the mixer and the said driving motor. By the present inventionthe difficulty of interconnecting the parts has been reduced to anabsolute minimum so that said driving connection can be readilyeffected.

The device of the present invention in addition to eifecting theadvantage set forth in the preceding paragraph also incorporates meanswhereby a flow of the mixed ingredients, investment, can be acceleratedinto the mold forming'device and said flow encouraging means, commonlycalled a vibrator, obtains its power from the same driving connection asbetween the motor and mixer.

It is therefore, the principal object of the present invention togenerally improve the structure of an investment mixer and the mode ofusing the same.

Another and important object of the present invention is the provisionof means whereby a mixer mixing element and a driving engine may bereadily connected and disconnected from one another.

A still further and relatively specific object of the present inventionis the provision of an improved coupling or clutch that may be readilycoupled between a driving motor and the mixer blade or paddle shaft forefficiently and conveniently actuating said mixing blade or paddle.

A still further object of the present invention is the provision of avibrator for vibrating an investment mixture with which is associated amold-forming device for causing a ready flow of the cementitiousinvestment mass from the mixer into the said mold-forming device or itscontainer.

It is also an object of this invention to provide a compact unit foraccomplishing the foregoing objects that is simple of construction andeconomical to produce and acquire while being consistent with the workto be obtained from the device.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification considered inconjunction with the accompanying drawings forming a part thereof and itis to be understood that any modifications may be made In the exactstructural details there shown and described, within the scope of theappended claims, without departing from or exceeding the spirit of theinvention.

In the drawings:

FIG. 1 is a side elevational view of a complete mechanism for effectingthe mixing of investment compositions.

FIG; 2 is an enlarged fragmentary sectional view through the mixer perse and its drive as seen from line 22 on FIG. 1.

FIG. 3 is a transverse sectional view through a portion of the drivemechanism as seen from line 33 on FIG. 2.

FIG. 4 is a vertical sectional view taken on line 44 on FIG. 1.

Throughout the several views of the drawings similar referencecharacters are employed to denote the same or similar parts.

Specifically, and referring to the drawings, the complete device of thepresent invention comprises an electric motor 10 operating at one endthereof a vacuum pump indicated in general by the reference numeral 11.he motor 10 operates at its other end the investment mixer, per se,indicated in general by the reference numeral 12, while the said motorat said end thereof in addition actuates the vibrator indicated ingeneral by the reference numeral 13.

The vacuum pump 11 is suitably enclosed in a housing 14 secured througha supporting bracket 15 to the motor 10. It is to be understood that themotor 10 has one end of its shaft, for the sake of this description, therear end 28', extending through the bracket 15 into the pump housing 14for actuating the pump element or elements therein. The pump housing 14has an inlet 16 connected through an elbow 17, or the like, with thecover 18 of an oiler and filter device 19. The oiler and filter devicecover 18 has connected therewith a nipple 29 to which, in turn, isconnected one end of a flexible conduit or hose 21.

The pump housing 14 is provided with an outlet, not shown, but withwhich outlet is connected a mufiier 22 of any suitable or desirableconstruction.

7 It is believed that the construction and operation of a vacuum pump iswell known and need not be ftnther described or illustrated. Briefly,however, the operation of this device is as follows:

Operation of the pump elements within the housing 14 through the motorshaft effects a suction through the flexible conduit or hose 21 and themember or nipple 26, into and through the oiler and filter unit 13-19.The discharge of the air and gases from the pump is through the muffler22. In order to determine the amount of vacuum being pulled by the pump,there is provided the usual vacuum indicator or gauge 23.

The unit is adapted to be suitably supported on a table or the likethrough, preferably, rubber feet 24 and 25 respectively secured to anddepending from plates or brackets 26 and 27 respectively, secured to anddepending from the motor 10 and vacuum pump attaching or mountingbracket 15.

i As seen in 2 the motor jecting fonwardly thereof -to-receive has itsshaft 28 proa driving sleeve '29. 29 has its central bore to a diameterto reshaft 28 and is retained on the The sleeve ceive the said motorshaft through a suitable set or dog screw 30 threaded through one sidethereof into a keyway 31 formed longitudinally of the said motor shaft28. The front or outer end of the sleeve bore 32 is outwardly tapered asat B3 forming, in effect, a cup :33 whose inner surface inwardly tapersor is funnel shaped. This cup constitutes one member of the drivingclutch, coupling, or the like, as presently be made clear, between themotor 10 and the mixer, per se, 12.

The vacuum mixer, per se, 12, is fully disclosed in the above identifiedpending application of Edmund A. Steinbeck, Jr. and Robert Nieman',Serial No. 255,704. This mixer, briefly, comprises a cup-like mixingmember or container 34 in which the ingredients are mixed with saidcontainer or member 34 having interiorly thereof a mixer blade or paddle35 secured to and carried by a driving shaft 36. The driving shaft 36 isrotatably mounted in a sleeve or bushing 37 pressedinto or cast within a'hollow upstanding'post or boss 38 from the container or member 34'closing lid or cover 39. In other 'words, the cup or mixing container 34is closed by the cover or lid '39 in which is journaled a shaft 36 thatcarries at its lower end and within the cup or 7 container 34, a paddleor mixing blade 35.

The cover or lid 39, to one side of the cylindrical post or boss 38 isprovided with an upstanding lug through which is formed an aperture orbore 40 communicating with the interior of the mixing cup or containerand which bore 40 receives the end of a coupling or nipple 41 which inturn has connected therewith the other end of the flexible conduit orhose 21. r The cover or lid 39 on the other side of the post or boss 38is provided with an extension 42 counterbored to receive the lower orinner end of a casting ring or sleeve 43 which is closed at its upper orouter end by a crucible former and sprue former carrier 44. The interiorof the casting ring or sleeve 43 is in communication with the interiorof the mixing cup or container 34 through an aperture 45 formed throughthe lid or cover 39.

Upwardly of the bushing 37 the mixing blade or paddle shaft 36 isprovided with a threaded reduced portion 46 received in a threadedsocket 47 in driven member 48. The driven member 48 has its body portionbeyond its threaded socket tapered as at 49 so as to readily enter thedriving cup 33' of the driving member or sleeve 29, and inwardly of itsouter end the driven member 48 is provided with a circumferential groove50 receiving a a relatively soft, preferably rubber, ring 51.

In practice, the ring 51 may be what is known as an O ring and whenmounted on the driven member 48 has an effective outer diameter lessthan the diameter of the outer end of the cup 33' while this diameter isgreater than the inner end of said cup, wherefore, the said ring willengage the tapered wall of the said cup at a point between its inner andouter ends. It should be noted that the driven member 48 and the ring 51together constitute or form the second or driven member of the drivingclutch, coupling, or the like, between the mixer, per se, and thedriving motor.

Secured to the front end of the motor 10, in any suitable or desirablemanner, is a housing 54 which supports the mechanism that forms thevibrator 13. As illustrated in the drawings, the housing 54 is somewhatbell shaped and includes a vertical wall 55 from the periphery of whichextends or projects the skirt 56. The housing 54 is secured in positionsthrough dog or clamp screws 57 extending through the housing skirt 55near its edge into engagement with the motor housing circularprojection58.-

The housing 54 has upstanding therefrom a sleeve 59 for a reciprocableplunger rod 60. The plunger rod 60 is adapted to be' reciprocatedthrough the sleeve 59and is retained within the sleeve and its path ofreciprocation may be controlled by any suitable or desirable means, thatshown in the drawings comprising the formation of a slot 61 in one sideof the plunger rod 60 cooperating with and receiving the inner end of ascrew, pin, or the like 62, carried by and projecting through the sleeve59. The plunger rod 60 is provided on its upper end with a head 63 ofconsiderable area with respect to the crosssectional area ofthe saidplunger rod 60. The head 63 is preferably circular in plan and isprovided with an upper surface 64 which, in practice, constitutes theplatform for the mixer when the vibrator is being used.

In normal practice, the plunger rod 60 is retained, yieldably, in aninoperative position by means of a coiled spring 65 which encircles thesaid plunger rod 60 and has one end abutting the upper end of the 59 andits other end abutting the lower surface of the head 63. The normalinoperative position of the plunger rod 60 is determined by the loweradd the slot 61 engaging with the screw, pin, or the like 62.

The plunger rod 60 is positioned to overlie the inner end of the drivesleeve 29 and'the said drive sleeve 29 below the said plunger rod 60 isprovided with flats, illustrated in the drawings at 66 and 67 and as atdiametrically opposite points on the said sleeve. It should be herenoted that a single flat may be employed or the number of said flatsincreased without changing the normal operation thereof. The said flats66 and 67 cooperate with the circumference of the driving sleeve, aswell as with one another, in acting as cams for actuating the vibrator,as will presently be made clear.

In operation and after the materials for forming the investmentcomposition, generally an aqueous solution and powder, have been placedin the mixing cup or container 34, the lid or cover 39tis placed thereonwhereupon the vacuum flexible conduit or hose 21 through the nipple orcoupling 41 is connected with the said mixing cup or container and themotor started for operating the vacuum pump as above set forth. Thevacuum pump withdraws all of the air and other gases within the saidmixing container on cup 34 and the casting ring or sleeve 43. In orderto insure a completeand effective vacuum within the said parts, all ofthe joints of the several elements are protected by a g ket, preferably,in the form of an 0 ring. In the drawings, particularly FIG. 2, the saidseveral 0 ring gaskets are respectively indicated by the referencenumeral 68.

After the vacuum pump 11 has been placed in operation the user merelyraises the investment mixer, per se, from the table or counter andpushes the mixing blade or paddle driving shaft member 48 through itsflexible driving element 51into engagement with the inclined or taperedwall 33 of the driving sleeve driving cup or socket 33. This connectionmay be eifected regardless of the speed of the motor 10 and without inany manner whatsoever slowing down or changing said speed,

as was necessary with the driving connection illustrated in the aboveidentified application. The user will retain the motor and theinvestment mixer, per se, indriving connection with one; another for thenecessary and desirable time of spatulation.

It will be understood that as the mixer paddle or blade 35 is driven,it, through the action of the notches. in its edges, breaks up theinvestment into ribbon-like layers, thereby exposing such layers to thevacuum for having any entrapped air or gases removed therefrom.

Upon, as noted above, the completion of the mixing of the ingredients,the operator merely withdraws the mixer, per se, from the motor sleeve29 for thereby breaking the connection'and permitting the mixer paddle3510 slow down and become idle.

The operator immediately upon retracting or'separating the mixer, perse, from the motor, turns the mixer upside guide sleeve 7 down to placethe outer face of the crucible former and sprue former carrier 45 of thevibrator head 63. At the same time, the user downwardly forces the saidmixer, per se, and compresses the spring 65 for causing the plunger rod60 to engage with the surface of the driving sleeve 28 immediatelytherebeneath. In other words, the plunger rod 60 is now riding on thesaid outer surface of the sleeve 29 which, as noted above, through theflats 66 and 67 thereon, acts as cams for alternately pushing the rod 60upwardly and allowing the said rod to drop onto the said flats 66 and67. Since the motor is rotating at a relatively high speed, this actioneffects a rapid vertical reciprocation of the said pin or rod 60 and theinvestment mixer held thereon. This causes a rapid vibration of themixer and a disturbance in the investment composition overcoming anyinertia that may be in said investment composition and causing same toflow from the mixing cup or container 34 through the port or opening 45into the mold forming housing or casting ring 43. This vibration, inaddition, causes the cementitious, semi-fluid investment composition topack within the said mold-forming housing or casting ring and to packaround the crucible forming portions of the crucible former and aroundthe sprue forming pin as well as around the pattern at the inner end ofthe said pin, all as is well known in the use of a vibrator.

From the foregoing it will be noted that there has been provided acompact unit for effecting the mixing of ingredients that form andconstitute an investment composition and in which the drive between saidmixer and its driving engine or motor is readily effected. It willfurther be noted that the compact unit readily removes any air or gasthat may be within the several housings of the mixer and casting ringand entrapped in the ingredients constituting the investmentcomposition. At the same time, there is provided a vibrator for insuringa motor having a shaft,

motor to be operated thereby, a coupleable driving member of a separablefriction drive device secured to the other end of the motor shaft, aninvestment mixer including a driven mixing element, a coupleable drivenmember of the separable friction drive device carried by the investmentmixer driven mixing element for frictional engagement with the drivingmember of the separable friction drive device, and means connecting thevacuum pump and investment mixer providing a suction passage toestablish and maintain a vacuum in the mixer.

2. A device of the class described the combination of a motor having ashaft, a vacuum pump secured to the motor and connected to the shaft atone end of the motor to be operated thereby, a coupleable driving memberof a separable friction drive device secured to the other end of themotor shaft, an investment mixer including a driven mixing element, acoupleable driven member of the separable friction drive device carriedby the investment mixer driven mixing element for frictional engagementwith the driving member of the separable friction drive device,

and a vibrator carried by the motor including an actuating devicesecured to and actuated by the motor shaft at the end thereof with whichthe separable friction drive device coupling member is associated.

3. A driving connection between a motor and an investment mixercomprising the motor having a driven shaft, a sleeve secured to saidshaft for rotation therewith,

on the surface or platform 64 plunger for effecting verticalrec'procation of the plunger relative to the housing.

5. A driving connection between ment mixer comprising the motor having adriven shaft,

vertically reciprocable plunger carried by said housing, means on saidsleeve within the housing engaging the plunger for eifecting verticalreciprocation of the plunger relative to me housing, and yieldable meansfor normally separating the plunger and sleeve.

. 7 '8 said sleeve within the housing engagingthe plunger for 1;784;307'Nelson' et a1. Dec. 9, 1930 effecting vertical reciprocation of theplunger relative '1,863,977 Forde et a1. June 21, 19.32 to-the' housing; a head secured to the plunger upwardly 2,036,713. McBath' Apr.7, 1936 of the housing; and yieldable means between the plunger2,453,914 Hollenback Nov. 16; 1948 head and housing for normallyelevating the plunger to 5 :2,556;263- Fiorini June 12; '1951 a-pointout of operation with the sleeve. 2,562,805 Martinez July 31, 1951 g 7 r2,605,086 Marco July 29, 1952 References Cited in the file of thispatent 2,637,936 en May 12, 1953 NI STATES PATENTS 2,666,307 Higert'Jan. 19; 1954 2,690,246 Kelleigh Sept.- 28, 1954 Steinbeck et al Jan.15, 1957 244,091 Tenney Ju1 12, 1881 10

1. A DEVICE OF THE CLASS DESCRIBED THE COMBINATION OF A MOTOR HAVING A SHAFT, A VACUUM PUMP SECURED TO THE MOTOR AND CONNECTED TO THE SHAFT AT ONE END OF THE MOTOR TO BE OPERATED THEREBY, A COUPLEABLE DRIVING MEMBER OF A SEPARABLE FRICTION DRIVE DEVICE SECURED TO THE OTHER END OF THE MOTOR SHAFT, AN INVESTMENT MIXER INCLUDING A DRIVEN MIXING ELEMENT, A COUPLEABLE DRIVEN MEMBER OF THE SEPARABLE FRICTION DRIVE DEVICE CARRIED BY THE INVESTMENT MIXER DRIVEN MIXING ELEMENT FOR FRICTIONAL ENGAGEMENT WITH THE DRIVING MEMBER OF THE SEPARABLE FRICTION DRIVE DEVICE, AND MEANS CONNECTING THE VACUUM PUMP AND INVESTMENT MIXER PROVIDING A SUCTION PASSAGE TO ESTABLISH AND MAINTAIN A VACUUM IN THE MIXER. 